Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD) have been applied as vapor deposition techniques for producing thin films for semiconductor devices.
Films of metal and metal silicide, particularly manganese, iron, cobalt, nickel, and ruthenium, are becoming important for a variety of electronics and electrochemical applications. For example, cobalt thin films are of interest due to their high magnetic permittivity. There are many reports of using cobalt thin films to form cobalt disilicide (CoSi2) for Ohmic contacts owing to its low resistivity in front-end-of-the-line processing of semiconductor devices. Cobalt containing thin films have been recently studied as Cu/low-k barriers, passivation layers, and capping layers for ultra large scale integrated devices.
Cobalt tricarbonyl nitrosyl, Co(CO)3(NO), is a known precursor used to form cobalt containing films. See, e.g., U.S. Pat. No. 4,748,045 to Ehrlich et al. and U.S. Pat. No. 6,444,263 to Paranjpe et al.
Cobalt containing film vapor deposition using Co-containing precursors, including Co(CO)3(NO), on copper and barrier layers, such as Ta, TaN, Ti, TiN, W, and WN, is also encompassed within the disclosures of PCT Pat App Pub WO2009/134925 to Yu et al. and US Pat App Pub Nos 2009/0269507 to Yu et al.; 2009/0053426 to Lu et al.; S. Ganguli et al, US2011/0124192; US2012/0252207) to Lei et al.
US 2008/0132050 to Lavoie discloses a method of forming a graded cobalt-containing barrier layer by forming a Co metal layer atop a CoN layer using any of at least 37 different Co-containing precursors, including Co(CO)3(NO), in any combination of PVD, ALD, or CVD processes followed by annealing.
Chemical vapor deposition of Cobalt from Co(CO)3(NO) has been studied and reported (A. R. Ivanova et al, J. Electrochem. Soc, 146 (6) 2139-2145, 1999; A. R. Ivanova et al, J. Electrochem. Soc., 148(1) C21-C27, 2001; Deo et al., Proceedings—Electrochemical Society (2003), 2003-8 (Chemical Vapor Deposition XVI and EUROCVD 14, Volume 2), 1008-1015). As reported in these articles, a temperature greater than 300° C. was necessary to obtain almost 100% cobalt film.
A need remains for processes to rapidly form pure cobalt films at low temperatures.
Notation and Nomenclature
Certain abbreviations, symbols, and terms are used throughout the following description and claims, and include:
As used herein, the indefinite article “a” or “an” means one or more; the terms “approximately” or “about” mean±10% of the value stated; and the term “selective deposition” means to deposit the desired layer on one surface of a multi-surface substrate (e.g., depositing a Co layer on a Si surface of a substrate, but not on the Pd surface of the same substrate).
As used herein, “first” and “second” denote a sequential order or two different layers on a substrate.
As used herein, the abbreviation “CVD” refers to chemical vapor deposition, the abbreviation “PECVD” refers to plasma enhanced chemical vapor deposition, the abbreviation “ALD” refers to atomic layer deposition, the abbreviation “PEALD” refers to plasma enhanced atomic layer deposition, the abbreviation “PVD” refers to physical vapor deposition, the abbreviation “XPS” refers to X-ray Photoelectron Spectroscopy, and the abbreviation “SEM” refers to scanning electron microscope/microscopy.
The standard abbreviations of the elements from the periodic table of elements are used herein. It should be understood that elements may be referred to by these abbreviations (e.g., Co refers to cobalt, Si refers to silicon, C refers to carbon, etc.).